This invention relates to a golf ball composition and, more particularly, to a golf ball using a matrix composite comprising a polymer and discrete particles of gel to vary the playability of a golf ball.
As described in U.S. Pat. No. 5,779,561 golf balls traditionally have been categorized in three different groups, namely as one-piece balls, multi-piece (two or more piece) solid balls and wound balls. Conventional multi-piece solid golf balls include a uniform or multi-layer solid resilient core having a cover of a different type of material molded thereon. Wound golf balls traditionally have included a liquid or solid center, elastomeric winding around the center, and a molded cover. Solid cores often are made of polybutadiene and the molded covers generally are made of natural balata, synthetic balata, ionomeric resins, crosslinked polyurethane, or thermoplastic polyurethane. A great deal of research continues in order to develop golf balls exhibiting the desired combination of carrying distance, durability (e.g. cut and abrasion resistance, and fatigue endurance), and spin.
U.S. Pat. No. 5,150,906 describes a golf ball comprising a hollow, spherical shell of a deformable polymeric material that is filled with either a liquid or a unitary, non-cellular core of a material having a central non-wound core, an inner and an outer layer. The core material may be added through a hole in the shell as a liquid, a gel or a melt.
U.S. Pat. No. 5,397,840 describes a golf ball cover comprising a non-ionic/ionic copolymer blend. A golf ball with the ionic/ionic copolymer blend exhibits no loss in coefficient of restitution (C.O.R.), and has equal resistance to cutting and cracking when compared to top grade golf ball covers made with one of the conventional 100% ionic copolymer blends.
A coated golf ball comprising a golf ball body and a paint layer is described in U.S. Pat. No. 5,789,486. The paint layer is comprised of a dispersion of internally-crosslinked polymer gel fine particles. The coated golf ball is claimed to have excellent coating characteristics including less sagging of the paint coat at the dimple edge, and maintenance of original flying characteristics.
A golf ball having a reduced spin rate is described in U.S. Pat. No. 5,827,133. In one embodiment of the invention, the golf ball is constructed with a fluid core either of a liquid or gelatinous substance. Such a construction is believed to render the golf ball less responsive to any initial spin imparted to the outer cover of the golf ball.
U.S. Pat. No. 5,820,489 describes a low spin golf ball comprising a core that further comprises a diene polymer having a Riehle compression of at least 0.075; and a cover having a Shore D hardness of at least 65. U.S. Pat. No. 5,580,057 also describes a low spin golf ball comprising a soft core and a hard cover to produce a resulting molded golf ball having a reduced spin rate.
U.S. Pat. No. 5,779,561 describes a multi-layer golf ball with a central core, an inner cover layer containing a non-ionomeric polyolefin material and a filler, and an outer cover layer comprising a resin composition. While the inner cover layer contains a non-ionomeric material, the outer cover layer may include an ionomer. The golf ball can be configured to have playability properties comparable to those of golf balls that contain higher quantities of ionomer. The core may be wound or non-wound, and include liquid, gel or solid cores.
Iononomeric resins are polymers containing interchain ionic bonding. Examples of ionomeric resins used for the construction of golf ball covers include those sold by E. I. DuPont de Nemours & Company, Wilmington, Del. ("DuPont") under the registered trademark "Surlyn" and by Exxon Corporation, Irving, Tex. (see U.S. Pat. Nos. 5,779,561 and 4,911,451; U.S. Pat. Nos. 5,779,561 and 4,911,451 are hereby incorporated by reference in their entirety) under the registered trademarks "Escor" and the trade name "lotek." Ionomeric resins have become the materials of choice for the construction of golf ball covers over the traditional balata (trans-polyisoprene, natural or synthetic) rubbers. The softer balata covers, although exhibiting good playability properties, lack the durability required for repetitive play.
While there are numerous commercial grades of ionomers available, the properties vary according to the type and amount of metal cations, molecular weight, composition of the base resin (i.e., relative content of ethylene and methacrylic and/or acrylic acid groups) and additive ingredients such as reinforcement agents, etc. Consequently there is a need for a composite structure wherein the playability properties are varied according to a set of parameters separate from and in addition to the molecular properties of the non-gel material (e.g. an ionomeric polymer.) More particularly there is a need for a composite material comprising of a non-gel material dispersed with discrete particles of gel to provide at least one continuous phase and at least one discontinuous phase. Such a composite structure will enjoy playability properties that additionally vary in accordance with the type of gel particles dispersed in the non-gel material.
A gelatinous elastomer composition is described in U.S. Pat. No. 5,633,286: that patent is hereby incorporated by reference in its entirety. The gelatinous elastomer composition is physically interlocked with an open cell sponge thereby displacing the air space within the sponge. Gel rigidity is found to be greater than the sum of the combined rigidity of the gelatinous elastomer composition and sponge alone. The gelatinous elastomer composite exhibited high elongation and tensile strength and excellent shape retention after extreme deformation under high-velocity impact and stress conditions.
While the prior art teaches various golf ball compositions, none of the prior art teaches a golf ball with a mantle, hard-cover layer or core comprising of discrete voids filled with a gel in order to alter the playability of the golf ball. In addition, none of the prior art teaches a non-wound golf ball with a solid core dispersed with discrete voids filled with a gel. More particularly, none of the prior art teaches a non-wound golf ball comprising a solid core comprising of discrete voids filled with gel and with good control and spin off the club similar to a more expensive wound golf ball.